Omidi, S. et al. 2019. Characterizations of regular and intra-regular ordered $\Gamma$-semihypergroups in terms of bi-$\Gamma$-hyperideals. Carpathian Mathematical Publications. 11, 1 (Jun. 2019), 136–151. DOI:https://doi.org/10.15330/cmp.11.1.136-151.